I have found some references to being able to use the Schick Twin with normal injector blades, but not more than one… on some images online the twin blade looks to be made of two blades that each are thinner than the normal blade… the resulting double blade seems to be a little wider and thicker than a modern single.
A modern single blade in an E2 injector.
A Schick Twin blade in the same razor – same razor and blade as the second to last image in last Thursdays post.
It is also interesting to see the ‘naked’ blade compared to normal injector blades (modern blade on the left and an original on the right); slightly staggered, and with cut-outs to allow cleaning.
I’m finding several fleaBay auctions for Twin blades, but most of them looks like NOS from late 80s or early 90s… plenty with Japanese or possible Chinese labelling that may be more recent though, hard to tell.